How do you read a binary clock?

Each column is one digit of the time in binary-coded decimal, with dots worth 8, 4, 2 and 1 from top to bottom. Add the lit dots in a column to get that digit. The decimal row below each column shows the answer.

Is the binary clock screensaver accurate?

Yes. It reads your device's own clock twice a second and encodes the exact hours, minutes and seconds. No internet connection is needed.

Can I turn off the decimal numbers?

Yes. The Show decimal row toggle hides the digit labels under each column for a pure binary display, or shows them so you can learn to read it.

Can the binary clock show a 12-hour time?

Yes. Set Hour format to 12-hour and the hour column rolls between 1 and 12 instead of 0 to 23. You can also hide seconds to drop to four columns.

Is the binary clock screensaver free?

Yes. It runs entirely in your browser with no download or account. Press ESC whenever you want to exit full screen.

Binary Clock Screensaver

The Binary Clock screensaver shows the time as columns of glowing dots, with each column a digit of the time written in binary-coded decimal. It reads your device's own clock, so the time it encodes is always accurate. It runs free in your browser with no download, and you press ESC to exit.

How the Binary Clock screensaver works

The saver reads new Date() twice a second and pads the time to two digits each for hours, minutes and seconds. Each digit gets its own column of four dots, weighted 8, 4, 2 and 1 from top to bottom.

For every column it tests which bits are set using a bitwise AND against those weights. A lit dot fills with your accent color and gains a soft glow; an unlit dot stays a hollow outlined circle, so the pattern is easy to scan.

Showing seconds gives six columns (HH MM SS); turning seconds off drops to four columns for hours and minutes only. A 12-hour format rolls the hour to a 1-to-12 range.

When Show decimal row is on, a small number prints under each column with the digit it encodes, which makes the binary easy to learn and to read at a glance.

A worked example

With the default cyan accent, seconds on, 24-hour format and the decimal row on, at 09:47:05 the six columns light the dots for 0 9 4 7 0 5, each glowing column labelled with its digit underneath.

Settings & tips

Keep Show decimal row on while you learn to read it; turn it off for a pure binary display.
Turn off Show seconds for a calmer four-column clock that updates only on the minute.
Use the Lit color control to set the glow of the active dots against the dark background.

Frequently asked questions

How do you read a binary clock?: Each column is one digit of the time in binary-coded decimal, with dots worth 8, 4, 2 and 1 from top to bottom. Add the lit dots in a column to get that digit. The decimal row below each column shows the answer.
Is the binary clock screensaver accurate?: Yes. It reads your device's own clock twice a second and encodes the exact hours, minutes and seconds. No internet connection is needed.
Can I turn off the decimal numbers?: Yes. The Show decimal row toggle hides the digit labels under each column for a pure binary display, or shows them so you can learn to read it.
Can the binary clock show a 12-hour time?: Yes. Set Hour format to 12-hour and the hour column rolls between 1 and 12 instead of 0 to 23. You can also hide seconds to drop to four columns.
Is the binary clock screensaver free?: Yes. It runs entirely in your browser with no download or account. Press ESC whenever you want to exit full screen.

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